The iOCT procedure for lower extremity PAD is fairly straightforward. An introducer is placed into the femoral artery. After which a wire is placed past the lesion of interest and the iOCT catheter is inserted. The catheter is then attached to an automated pullback device. Next an optical medium is needed to displace the erythrocytes. Due to the high resolution of the iOCT this is necessary for a cleaner image to analyze. At the time of injection of the optical medium a sensor triggers the catheter to be withdrawn (distal to proximal) at anywhere from 10-25 mm/sec. The images are captured and processed and arterial plaque can be characterized.